As methods for debugging a sequence program, there are a method of performing a current-value changing process and a method of conducting a test with an execution condition. In these methods, however, a setting operation requires some work. The current-value changing process is a process of manually changing a memory value during execution of a sequence program. To perform the current-value changing process, a dedicated dialog screen needs to be opened to specify the number of a memory and the value thereof to be changed. The test with an execution condition has a function of setting the value of a memory to a specified value at a specific position (a condition) in a sequence program. In this function, the condition, the number of the memory, and the value thereof to be changed need to be specified after opening a dedicated dialog screen other than a program editor.
As another method for debugging a sequence program, there is a method of performing a series of operations, for example, as indicated by the following (1) to (6) (see Patent Literature 1, for example). In the following descriptions, a sequence program that runs as an actual product is referred to as “official program”.    (1) An official program is created and converted to be executable by a controller.    (2) The official program is written to the controller and executed by the controller, and the operation thereof is confirmed on a monitor or the like.    (3) When a bug is detected during execution, a debugging program is added to a bugged position that is to be debugged in the official program. The debugging program is added, for example, by inserting a circuit element of “OR TRUE” to a condition portion of a circuit that is to be always ON. The entire program having the debugging program inserted thereto is then converted to be executable by the controller.    (4) The entire program including the debugging program is written to the controller and executed by the controller, and the operation thereof is confirmed again on the monitor or the like.    (5) In a case where the operation is confirmed by switching execution between the official program and the debugging program, the above (3) and (4) are repeated. Specifically, correction, conversion, write, and operation confirmation of the entire program are repeated.    (6) After a normal operation of the official program is confirmed, the debugging program portion is deleted. The official program is converted again to be executable by the controller and is written to the controller. The controller then performs processing using the official program.